(a) Field of the Invention
The present invention relates to a paintball gun percussion mechanism, and more particularly to a propeller provided with a retaining wall to reciprocally move between a first airway and a second airway in a barrel to launch a projectile.
(b) Description of the Prior Art
U.S. Pat. Nos. 5,881,707, 5,967,133, 6,035,843, 6,474,326, and 6637421 disclosed a 2-step percussion mechanism of a paintball gun of the prior art. As shown in FIG. 7, a percussion mechanism includes a barrel (B), a piston (C), and a push rod (D). The piston (C) is disposed in a middle section of the barrel (B). The push rod (D) is disposed in a rear section of the barrel (B) to constitute 2-step percussion mechanism operating on two separately provided portions. Accordingly, gas is separately inputted into the middle section and the rear section of the barrel (B). The air input to the rear section of the barrel (B) is used to propel the push rod (D) for the push rod (D) to plunge against the piston (C) to slide in the barrel (B) thus to push a paint pellet, which is in turn fired when the pressure of the air in the middle section of the barrel (B) becomes higher than that of a critical point.
FIG. 8 shows another prior art as taught in U.S. Pat. Nos. 6,810,871, 7,044,119, 7,121,272, and 7,185,646. A paintball gun percussion mechanism includes a barrel (E), a front outer box (F), a rear outer box (G), a propeller (H) and a bolt (I). Both the front outer box (F) and the rear outer box (G) are mounted in the barrel (E) and penetrated by the propeller (H). One end of the propeller (H) is inserted by the bolt (I). Each of the front outer box (F) and the rear outer box (G) has provided on their inner walls a retaining wall and a washer; and corresponding retaining wall and washer are provided on the outer wall of the propeller (H) for the propeller (H) to slide back and forth in the front outer box (F) and the rear outer box (G). Compressed air is filled in the rear outer box (G) to push forward the propeller (H) into the front outer box (F). Once the propeller (H) clears out of the bolt (I), the compressed air stored in the rear outer box (G) is conducted into the propeller (H) to propel a paint pellet.
However, either of the prior art is comprised of multiple different members which consume longer time in assembly and higher production cost; the assembly comprised of multiple members is vulnerable to failure and makes service inconvenient; furthermore, multiple retaining walls and washers cause great friction by consuming too much compressed air and are subject to earlier tear and wear.